Combining Particle Tracking Models and Otolith Chemistry to Study Active Movement of Larval Yellow Perch in Western Lake Erie

Swimming behavior can impact the direction and magnitude of plankton transport and dispersal. We evaluated the importance of swimming behavior to dispersal of larval Yellow Perch (YP) in western Lake Erie, a region characterized by habitat heterogeneity created by the Maumee River Plume (MRP). MRP waters have a distinct, temporally stable chemistry signature that is imprinted in larval YP otoliths inhabiting the plume. Using otolith chemistry and spatial distribution data, we determined that many larval YP (<33 days) found in MRP had inhabited the plume throughout their life. Using these observations, we ran particle tracking models under different behavior scenarios to determine how they were able to stay in the MRP. We found that modeled larvae that followed simple behaviors (i.e., swim towards river mouth) were able to stay within the plume, whereas those that were treated as passive particles or swam in random directions were advected from the plume. Thus, observed patterns in otolith chemistry could not be explained without consideration for active, orientated movement. Because larval YP that inhabit the MRP have lower mortality rates than non-MRP fish, our results suggest that active swimming behavior plays an important role in fish surviving to the juvenile stage.